<?php

namespace Aws\Api\Parser;

use Aws\Api\StructureShape;
use Aws\CommandInterface;
use Aws\Exception\AwsException;
use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\StreamInterface;
use GuzzleHttp\Psr7;

/**
 * @internal Decorates a parser and validates the x-amz-crc32 header.
 */
class Crc32ValidatingParser extends AbstractParser {
	/**
	 * @param callable $parser Parser to wrap.
	 */
	public function __construct(callable $parser) {
		$this->parser = $parser;
	}

	public function __invoke(
		CommandInterface  $command,
		ResponseInterface $response
	) {
		if($expected = $response->getHeaderLine('x-amz-crc32')) {
			$hash = hexdec(Psr7\Utils::hash($response->getBody(), 'crc32b'));
			if($expected != $hash) {
				throw new AwsException(
					"crc32 mismatch. Expected {$expected}, found {$hash}.",
					$command,
					[
						'code' => 'ClientChecksumMismatch',
						'connection_error' => true,
						'response' => $response
					]
				);
			}
		}

		$fn = $this->parser;
		return $fn($command, $response);
	}

	public function parseMemberFromStream(
		StreamInterface $stream,
		StructureShape  $member,
		                $response
	) {
		return $this->parser->parseMemberFromStream($stream, $member, $response);
	}
}
